Mullite vs. Silicon Nitride
Mullite belongs to the oxide-based engineering ceramics classification, while silicon nitride belongs to the non-oxide engineering ceramics. There are 17 material properties with values for both materials. Properties with values for just one material (7, in this case) are not shown.
For each property being compared, the top bar is mullite and the bottom bar is silicon nitride.
Metric UnitsUS Customary Units
Mechanical Properties
| Compressive (Crushing) Strength, MPa | 800 | |
| 600 to 2950 |
| Elastic (Young's, Tensile) Modulus, GPa | 110 to 170 | |
| 140 to 310 |
| Flexural Strength, MPa | 130 to 160 | |
| 130 to 810 |
| Fracture Toughness, MPa-m1/2 | 2.0 | |
| 3.1 to 6.2 |
| Poisson's Ratio | 0.25 | |
| 0.24 to 0.27 |
Thermal Properties
| Maximum Temperature: Mechanical, °C | 1680 | |
| 1000 to 1330 |
| Maximum Thermal Shock, °C | 170 to 230 | |
| 290 to 750 |
| Specific Heat Capacity, J/kg-K | 950 | |
| 720 to 800 |
| Thermal Conductivity, W/m-K | 3.5 to 11 | |
| 12 to 31 |
| Thermal Expansion, µm/m-K | 5.8 | |
| 2.5 to 3.2 |
Electrical Properties
| Dielectric Constant (Relative Permittivity) At 1 MHz | 6.3 | |
| 8.0 to 10 |
| Dielectric Strength (Breakdown Potential), kV/mm | 16 to 17 | |
| 18 |
| Electrical Resistivity Order of Magnitude, 10x Ω-m | 10 to 11 | |
| 11 to 12 |
Otherwise Unclassified Properties
| Density, g/cm3 | 2.7 to 3.0 | |
| 2.2 to 3.4 |
Common Calculations
| Stiffness to Weight: Axial, points | 22 to 31 | |
| 34 to 53 |
| Stiffness to Weight: Bending, points | 58 to 62 | |
| 65 to 78 |
| Thermal Diffusivity, mm2/s | 1.4 to 3.7 | |
| 7.5 to 13 |